For centuries individuals have used key rings to hold, organize, and easily transport the keys they use on a regular basis. Some examples of this type of key ring are disclosed in the following United States Patents, the entire contents of which are all hereby incorporated by reference: U.S. Pat. No. 603,247 entitled “Key-Holder” (“247 patent”), U.S. Pat. No. 1,462,205 entitled “Key Ring and the Like,” and Pat. No. D666,407 entitled “Key Ring.” These style key rings have the advantages of being durable and compact. The disadvantage, however, of these type of key rings is—it is often very difficult to separate the rings in order to add or remove keys.
Indeed, the '247 patent sought to overcome the difficulty of adding or removing keys. According to the inventor, his “invention relates more particularly to key-holders commonly known as ‘split-rings,’ but is also applicable to other forms of key holders composed of a single piece of wire or strip of metal in which a separation of overlapping portions of the wire or metal is requisite for the insertion or removal of a key. Split rings as commonly constructed have their free ends flush with the body of the ring, and when composed of specifically stiff or heavy metal it is extremely difficult to expand them sufficiently for the insertion or removal of a key without other aid than the fingers and the use of a knife-blade or other suitable article for this purpose . . . ” '247 patent at 8-22. The '247 patent went on to solve this problem by disclosing a key holder that would “admit of a ready separation of the parts without other aid than the key itself when being applied to the holder and which may be readily separated by hand in removing a key therefrom;” '247 patent at 34-38. Although the '247 patent issued in 1898, still, over a century later, modern day key rings are very difficult to separate in such a way so as to be able to add or remove a key.
FIG. 1 is a perspective view of a typical prior art key ring 100. As can be seen in FIG. 1, prior art key rings 100 typically consist of two concentric approximate circles 110, 120 proximal to one another. The lower approximate circle 110 and the upper approximate circle 120 are made of a single wire 102, which has been bent to form the two concentric approximate circles 110 and 120. One of the reasons that the two concentric approximate circles 110 and 120 are referred to as “approximate circles” and not just “circles” is because, as can be seen in FIG. 1, starting neither of the approximate circles 110, 120 is a comprised of a full 360-degrees of metal, or alternative material, within a single plane. This design feature allows a user to longitudinally displace an end, e.g., 112 of an approximate circle 110 in order to add or remove a key.
Keeping keys securely in place is an obvious goal of any key ring. In order to keep keys in place, key rings must be able to withstand radial and orthogonal, out of plane forces that will be placed upon the key ring during ordinary use. Referring to FIG. 1, latitudinal forces would occur both as latitudinal forces along the x-axis 160 and longitudinal forces along the y-axis 165. Prior art key rings 100 are able to withstand substantial radial forces without compromising the integrity of the key ring's 100 ability to keep the keys secure. This is a function of the fact that prior art key rings 100 are typically comprised of two concentric approximate circles of wire 110, 120 having a fairly large relative wire gauge diameter to the wind diameter of the concentric circles.
In terms of orthogonal force, it is desirable for the key ring to require sufficient orthogonal such that keys do not easily fall off of the key ring unintentionally. The orthogonal force should not, on the other hand, be so great that it is difficult to add or remove keys. The orthogonal force required to displace an end 112 of an approximate circle 110 sufficiently to facilitate the addition or removal of a key depends upon the ratio of the area moment of inertia (of the key ring cross section) to the diameter of the key ring. The area moment of inertia is proportional to the thickness of the key ring and the band width, defined as the difference between the outer and inner radii. Most key rings are designed with a sufficiently large wire gauge diameter so as to resist radial forces exerted on the key ring. However, the round nature of the wire used creates an equally resilient geometry resisting orthogonal forces. This results in a burdensome task for the user to overcome the orthogonal force required to add or remove keys.
Because of this difficulty, there are numerous patents directed toward devices that assist individuals in separating the concentric rings of a typical key ring in order to add or remove keys. As examples, the following U.S. patents and patent applications, each of the contents of which are hereby incorporated by reference, are directed towards devices that assist a user in adding or removing a key from a traditional key ring: US2009/0235705 entitled “Key Ring Tool,” U.S. Pat. No. 6,681,608 entitled “Key Ring Opener Assembly,” and U.S. Pat. No. 6,860,130 entitled “Easy-to-Maneuver Key-Ring.” While these tools can overcome the difficulty of adding or removing keys from modern day key rings, they do not overcome the original problem presented in the '247 patent, i.e., adding or removing keys from a key rings was difficult to do in the late 1800's without the assistance of extra tools; and adding or removing a key from a key ring is still difficult to do over a century later without using a separate tool.
Some inventors have addressed this long-standing problem by altering the basic shape of the key ring. By way of example, all of the contents of which are hereby incorporated by reference, U.S. Pat. No. 803,839 entitled “Key-Ring,” disclosed carabiner-style triangular and square key rings, while U.S. Patent Application No. 2008/0087063, entitled “Key Ring Assembly,” was directed toward a key ring having a light bulb shape. While these types of key rings are easier to open than the traditional key rings described above, they are bulkier to carry, and therefore less desirable to a substantial number of consumers.
There is, therefore, a need in the art for a round key ring that is capable of securely holding one's keys, while simultaneously providing an easy means for adding and removing keys without the need to rely on a separate tool or to risk bending one's fingernails, which is painful and annoying.